Hillary Clinton still leads the Democratic field in Iowa, but according to a new Public Policy Polling survey of “usual Democratic voters” in the Hawkeye state independent Vermont senator Bernie Sanders is making gains there.

A majority of Iowa Democrats, 52 percent, still support Clinton, while Sanders has 25 percent. That represents what PPP calls a “decent amount of tightening” in the Democratic race since April, with Clinton’s support dropping from 62 percent and Sanders’s up from 14 percent.